Debt Confusion?

I had to pay medical bills over credit card bills, and I get a call from collector saying they are going to sign off my debt to go to litigation, and then the judgement more than likely will be a lien on my name! oky so then i call a credit counsleing and their advice is to pay 600 to them and they can take it off my credit name if they dont respond in 30 days. My debt is 1800.00, I am 19, and a Student. I cant get a co signer on a loan I am on my own, so I cant get approved for a loan. I see everyone is saying do it on your own what a credit repair company does, but where do i start from?